[Qemu-devel] [PATCH v4 00/17] blockdev: Further BlockBackend work

[Max Reitz]

This series appears to reinvent itself with every revision. This time,
its main implication is that BBs are no longer automatically treated as
monitor-owned, and that a BB's name is tightly tied to the monitor
reference (it is considered equivalent to that reference).


v4:
- Tightly tied a BB's name to the monitor reference [Kevin]
  - Added two patches from my "blockdev: (Nearly) free clean-up work"
    series which are required so a BB does not need to have a name when
    bdrv_open() is invoked for its BDS tree
- Added a missing monitor_remove_blk() to the error path of
  hmp_drive_add() [Kevin]
- v3 just made blk_backends contain all BBs and then added another
  list called monitor_block_backends. v4 instead renames blk_backends to
  monitor_block_backends (because both are supposed to be the same,
  basically) and then adds a new list containing all BBs.
  [Markus/Kevin]
- blk_hide_on_behalf_of_hmp_drive_del() does a bit more than what
  monitor_remove_blk() does; namely, it invokes bdrv_make_anon() on the
  BDS. We should probably continue to do so.
- Use blk_is_inserted() instead of blk_is_available() for
  blk_commit_all() [Kevin]


Patch justifications:
- 1: General clean-up.
- 2: Clean-up which is nice to have for patch 7 which renames
     blk_backends to monitor_block_backends.
- 3: In order to move bdrv_commit_all() to the BB level (patch 12),
     first we need to introduce a BB-level function...
- 4: ...and then we have to use it.
- 5: After this series, BBs will no longer have a name before
     monitor_add_blk() is called; therefore, we should not try to print
     the device name when an image is opened (the filename is more
     interesting anyway)
- 6: Similarily to patch 5, this removes the device name from an error
     message emitted during image opening.
- 7: blk_backends to me personally implies this was a list of all
     BlockBackends. It actually is not. Therefore, this patch renames it
     to a more precise monitor_block_backends.
- 8: As this series makes it more clear that not all BlockBackends need
     to be referenced by the monitor, this patch consequently adds a
     list of truly and unconditionally all BlockBackends for whenever we
     need to iterate through really all of them.
- 9: This patch moves the name management for BlockBackends from
     blk_new(), blk_delete() and blk_hide_on_behalf_of_hmp_drive_del()
     into new functions monitor_add_blk() and monitor_remove_blk().
     These functions are still invoked in blk_new() etc., so nothing
     changes to the outside yet.
- 10: This patch drops the implicit calls of monitor_add_blk() and
      monitor_remove_blk() and thus makes the distinction between a BB's
      existence and whether it is owned by the monitor externally
      visible.
- 11: Clean-up patch.
- 12: More or less a clean-up patch.
- 13: Required so we can drop bdrv_states.
- 14: Required so we can drop bdrv_states.
- 15: Required so we can drop bdrv_states.
- 16: Clean-up and required so we can drop bdrv_states.
- 17: Clean-up and preparation for the follow-up series.


git backport-diff against v3:

Key:
[----] : patches are identical
[####] : number of functional differences between upstream/downstream patch
[down] : patch is downstream-only
The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively

001/17:[----] [--] 'monitor: Use BB list for BB name completion'
002/17:[down] 'block: Use blk_next() in block-backend.c'
003/17:[----] [--] 'block: Add blk_commit_all()'
004/17:[----] [--] 'block: Use blk_{commit,flush}_all() consistently'
005/17:[down] 'qapi: Drop QERR_UNKNOWN_BLOCK_FORMAT_FEATURE'
006/17:[down] 'block: Drop BB name from bad option error'
007/17:[down] 'blockdev: Rename blk_backends'
008/17:[down] 'blockdev: Add list of all BlockBackends'
009/17:[down] 'blockdev: Separate BB name management'
010/17:[down] 'blockdev: Split monitor reference from BB creation'
011/17:[0014] [FC] 'blockdev: Remove blk_hide_on_behalf_of_hmp_drive_del()'
012/17:[0002] [FC] 'block: Move some bdrv_*_all() functions to BB'
013/17:[0002] [FC] 'block: Add bdrv_next_monitor_owned()'
014/17:[----] [-C] 'block: Add blk_next_root_bs()'
015/17:[----] [--] 'block: Rewrite bdrv_next()'
016/17:[----] [--] 'block: Use bdrv_next() instead of bdrv_states'
017/17:[----] [-C] 'block: Remove bdrv_states list'


Max Reitz (17):
  monitor: Use BB list for BB name completion
  block: Use blk_next() in block-backend.c
  block: Add blk_commit_all()
  block: Use blk_{commit,flush}_all() consistently
  qapi: Drop QERR_UNKNOWN_BLOCK_FORMAT_FEATURE
  block: Drop BB name from bad option error
  blockdev: Rename blk_backends
  blockdev: Add list of all BlockBackends
  blockdev: Separate BB name management
  blockdev: Split monitor reference from BB creation
  blockdev: Remove blk_hide_on_behalf_of_hmp_drive_del()
  block: Move some bdrv_*_all() functions to BB
  block: Add bdrv_next_monitor_owned()
  block: Add blk_next_root_bs()
  block: Rewrite bdrv_next()
  block: Use bdrv_next() instead of bdrv_states
  block: Remove bdrv_states list

 block.c                                       |  86 +++-------
 block/block-backend.c                         | 228 ++++++++++++++++++--------
 block/io.c                                    |  20 ---
 block/parallels.c                             |   2 +-
 block/qcow.c                                  |   8 +-
 block/qcow2.c                                 |  30 +---
 block/qed.c                                   |   9 +-
 block/sheepdog.c                              |   4 +-
 block/vdi.c                                   |   2 +-
 block/vhdx.c                                  |   2 +-
 block/vmdk.c                                  |  13 +-
 block/vpc.c                                   |   2 +-
 blockdev.c                                    |  44 +++--
 cpus.c                                        |   5 +-
 device-hotplug.c                              |   4 +-
 hw/block/xen_disk.c                           |   2 +-
 include/block/block.h                         |   4 +-
 include/block/block_int.h                     |   4 -
 include/qapi/qmp/qerror.h                     |   3 -
 include/sysemu/block-backend.h                |  15 +-
 monitor.c                                     |   7 +-
 qemu-char.c                                   |   3 +-
 qemu-img.c                                    |  50 +++---
 qemu-io.c                                     |   2 +-
 qemu-nbd.c                                    |   4 +-
 stubs/Makefile.objs                           |   3 +-
 stubs/bdrv-next-monitor-owned.c               |   8 +
 stubs/{bdrv-commit-all.c => blk-commit-all.c} |   4 +-
 tests/qemu-iotests/036.out                    |  16 +-
 tests/qemu-iotests/051.out                    |   8 +-
 tests/qemu-iotests/051.pc.out                 |   8 +-
 tests/qemu-iotests/087.out                    |   2 +-
 32 files changed, 310 insertions(+), 292 deletions(-)
 create mode 100644 stubs/bdrv-next-monitor-owned.c
 rename stubs/{bdrv-commit-all.c => blk-commit-all.c} (53%)

-- 
2.7.3